If the oldest profession is prostitution, the second oldest pastime (the very oldest being left to the imagination) is heckling. There is, too, no more timeless heckle of the cautious leader than “Why don’t you do something!”

In the Middle East crisis, as on other issues, there are two Barack Obamas: the transformative historical figure and the pragmatic American president. Three months after a Tunisian fruit vendor set himself aflame and ignited a political firestorm across the Arab world, the president is trumping the trailblazer.

With the spread of antigovernment protests from North Africa to the strategic, oil-rich Persian Gulf, President Obama has adopted a policy of restraint. He has concluded that his administration must shape its response country by country, aides say, recognizing a stark reality that American national security interests weigh as heavily as idealistic impulses. That explains why Mr. Obama has dialed down the vocal support he gave demonstrators in Cairo to a more modulated call for peaceful protest and respect for universal rights elsewhere.

This emphasis on pragmatism over idealism has left Mr. Obama vulnerable to criticism that he is losing the battle for the hearts and minds of the Arab street protesters. Some say he is failing to bind the United States to the historic change under way in the Middle East the way that Ronald Reagan forever cemented himself in history books to the end of the cold war with his famous call to tear down the Berlin Wall.

“It’s tempting, and it would be easy, to go out day after day with cathartic statements that make us feel good,” said Benjamin J. Rhodes, the deputy national security adviser, who wrote Mr. Obama’s soaring speech in Cairo to the Islamic world in 2009. “But ultimately, what’s most important is achieving outcomes that are consistent with our values, because if we don’t, those statements will be long forgotten.”

From the very start, one strain of conservative critic, bound to find fault with the internationalism of Obama, has heckled the President for any hopeful voicing and a failure to adequately support what should be autocratic allies only of necessity and never of choice. Another kind, in the likes of Joe Lieberman and the illustratively unprincipled John McCain, has never passed a dark alley resounding in commotion without setting to rush down it unaware of what lies in wait at the other end. Whereas once conservatism called for a caution of “foreign entanglements,” now incorrigibly reflexive critics of any liberal’s pragmatic caution cry “ditherer” – just as they did when Obama patiently thought through his Afghan strategy in the second half of 2009, and as if, preposterously, the Middle East were Eastern Europe.

Now, we have the added cries of humanitarian outrage from the center and left. Christopher Hitchens and Leon Wieseltier, both of whom I admire, are nonetheless, both masters of moral high dudgeon, about the persuasive evidentiary nature of which we can say that it is highly moralizing and morally dudgeon. From Wieseltier there has even come, in echo of the Right, the notion that Obama (and presumably the Republican Robert Gates and Hilary Clinton, too, neither of whom has shown any daylight from Obama) is stricken, and deterred from bold action, by postcolonial guilt. Never, perhaps, has any President more than this President of modern, amorphous identity had more people read more of their own projections on to him. To be haunted by postcolonial guilt would indeed be disabling and weak. To shape policy in the knowledge of the colonial past, however, and its lingering influence, and of how its presence in the consciousness of those once colonized may help determine the reaction to and the consequences of our actions – that is a political acumen much longed for in the previous administration. There will always be those whose ideological adamance dictates policy and action loosed from historical understanding. They will always stumble the nation into the future.

More pointedly:

Why Libya? Why not Sudan, in Darfur, where over three hundred thousand have died, dwarfing any Libyan toll? Why not the Congo, where, in a widespread African war, over five million may have died through two decades, perhaps half of them children under age five, with as many as forty-five thousand a month dying as recently as 2009? Is it because television and celebrity journalists were not in those places to mark those wars as events of moral and historic weight? Because their victims do not possess cell phones and twitter accounts? Shall American foreign policy be directed by a media-shaped consciousness?

After a decade of two poorly prosecuted wars, the consequent military strain and the nation’s current economic strains, how many military engagements can the U.S. singly pursue? And with commitments, such as in Korea, that could, recent events remind, be called upon at any time – how many engagements? For all the greater evil of Saddam Hussein, had even George Bush not been able to persuade many of the threat of WMD and possible aid to Al-Qaeda, there would have been no action in Iraq. What is the deeply-considered policy rationale – beyond our horror and our hearts – for unilateral engagement in Libya?

If the U.S. unilaterally imposes a no-fly zone in Libya, and that is insufficient – as it now appears it might be – to help the rebels win the day, do we abandon them to their fates then ? Or are we then pressed to enter one step further into military support and alliance, as Bill Kristol would ever barreling draw us? What do we know – beyond the happy dream of Arab democracy and of commitment, at last, to liberty – of the disparate elements and forces that oppose Qaddafi and those that might win the next day in taking his place? Enough to offer the lives of still more American sons and daughters on their behalf?

If, while we are engaged in Libya, Bahrain erupts again, as now appears to have happened, then Yemen – two countries strategically more significant – do we engage in those countries, too, in support of still more outgunned rebellious citizens? Are we then able? Is the U.S. now to be midwife to a diverse and widespread Mideast revolution? Is such military midwifery now the American prime directive? What is the rationale for where and when – only the distress of knowing the immediate iniquity? And if we are once again taken by surprise by events we cannot predict? What is the limit? What actions of greater import might be precluded by our rush to act out of no other impetus but the awfulness of some event now, in a world that offers no end of awful events?

The greatest question of all: what vision is there of the future role of the United States, influenced by anything other than vestigial post Second World War and Cold War reflexes? Conservatives commit ever more to the chauvinism of an actual Exceptionalist American superiority, a superiority that justifies what was the ad hoc development of World War Two – the extension across the globe of the U.S. as, now, a sole self-perpetuating and self-justifying imperial superpower, committed both to its own boundless interests and superiority and to the maintenance, unilaterally, of a minimal world order. Is this the vision? If so, it is a radically altered understanding of the American experiment, and little in the reading of history or the prospects of other nations recommends it as actually visionary and sustaining. And when liberals who might otherwise disdain such a mission nonetheless grasp at it circumstantially to promote impulsive humanitarianism, they abandon any greater vision too.

Cries of pitiful gianthood because some other nation acts in any manner before us – France recognizing the Libyan rebels – are merely jejune. Let it be. Let it be more. Let France actually do something. It could. For if the result of American leadership of the “free world” for many decades is that at its end no other nation but the U.S. can lead in defense of liberty, then by any normal standard of leadership the U.S. will have failed. Signs are that the U.S. has been acting behind the scenes to seek, as it should, multi-lateral support for the Libyan rebels. That is a different kind of leadership. Signs, in fact, of an outcome to those efforts are not good. That is the world we live in. The U.S. cannot, should not, preside over the international order. It cannot give Europe a backbone, however much it might try over and over to stand the fellow up straight .

There will be times for the United States to act on its own in its pressing interests. They should be few and far between. They should be actions that devise or maintain a course clearly envisioned, maneuvers carefully plotted after patient reading of the charts and the winds. So far, there are ever ready catcalls from the sailors, crying to turn back or to blow through the straits. But there’s only one captain in sight.